house underpinning/insurance

Is this prior to any actual subsidence being observed?

Badly.

Spot on.

Agreed it usually a red flag.

However, in this case it sound as if the existing structure is OK, and the underpinning/re-inforcing of foundations is only to cope with the alterations?

Get the Structural Eng to call it re-inforcing or somesuch, ditto on all other paperwork/quotes JUST to underline the real reason for doing it.

Phil.

e.g.often has to be done when removing an internal loadbearing wall, as the 'pillars' left supporting the steel (supporting everything above) need a more substantial foundation now that it's area has been drastically reduced.....

Don't understand why, provided the underpinning is competently undertaken.

We were underpinned around 25 years ago, due to subsidence. There has been no movement since, the whole of the outside brickwork was repointed at that time and no cracks have reappeared.

In message , Tim Streater writes

Yes.

Exploratory digs have found what is considered to be inadequate corbelling.

I think this is probably the issue.

London row housing. Basement, two further floors and a pitched slate roof.

At some later stage, the rear wall was opened and a two storey flat roofed extension added across about half the width.

Most of the neighbours have created a fourth floor by bringing the roof out in a rectangular full width dormer (is that Mansard?)

Mansard is the usual pattern here in central London, though I would not describe it as 'rectangular'. Mansard is double pitched: a steep (almost vertical) bit at the bottom and and shallower pitch at the top, with a dormer window in the steep bit.

So is the deal that you're concerned that the insurers will just latch on to the word "underpinning"? Can't the work be labelled as "works necessary to improve the foundations needed since an extra story is being considered" or some such?

I don't think so: Its more likely that a job well done would improve saleability.

It may be an issue with insurance - although it shouldn't be

My experience of 15 years ago:

Victorian terraced house with some slight cracks in wall. Nothing to worry me, but to prove to future buyers, I called in the insurance co to make a 'claim' (i.e., have them monitor the wall). After a year they duly reported that there was no movement, and that any claim for patching the plaster, etc., was within the excess.

Come time to sell, one of the potential buyers wasn't able to get buildings insurance, as "we don't insure buildings with a history of claims for subsidence"!

In message , Hugo Nebula writes

Yes. Exactly my concern.

I have passed on the suggestion to avoid *underpinning* terminology and to emphasise *work necessitated by additional structural load*:-)

Currently, a further expert is considering the need/advisability. Foundation corbelling has been found but not considered adequate where a soil pipe has been fitted after the original construction.